[Mailman-Users] New list's SMTP failures

Hello,

On a server which hosts several mailman lists, a new list is exhibiting odd behavior for owner email addresses. There are two owners, and both are receiving post emails, but are also bouncing what I assume are administrative emails.

The smtp-failure log looks like:

Nov 01 09:37:09 2017 (1387) delivery to <scrubbed> failed with code 553: 5.1.8 <scrubbed>... Domain of sender address mailman-bounces@com does not exist

Note that the sender address is incorrect (default value?). Regular posting emails are delivered with the correct sender address (foo-bounces@domain.com).

Using config_list to inspect the non-working list against a working list produces only the expected differences.

Where should I look next?

Thank you.